1. Field of the Invention
The present invention relates to a battery control circuit to be mounted on a power supply device using an electric storage means such as a lithium secondary battery, a nickel-metal hydride battery, a lead battery, or an electric double-layer capacitor.
2. Description of the Related Art
In a power supply device, a distributed electric power storage device, an electric vehicle, or the like that uses an electric storage means such as a battery, a battery control circuit for managing the state of the electric storage means is mounted. A typical example of the state of the electric storage means to be managed by the battery control circuit is a State of Charge (SOC) indicating how much the electric storage means is charged or how much dischargeable electric charge remains.
In order to optimally use the electric storage means, it is necessary to take, for example, a measure to reduce the SOC if the SOC is too high or a measure to prevent a further drop of the SOC if the SOC is too low. In addition, when a power supply device uses multiple electric storage means which are connected in series, a SOC balancing function to keep the distribution of SOCs of the respective electric storage means within a certain range is needed to maximize the performance of the electric storage means.
As a method for SOC balancing of a multi-series battery among those mentioned above, a method is proposed in which voltages of blocks each including a certain number of battery cells are measured with a voltage detection circuit, and all of hardware means powered by the block having a high voltage of the blocks are turned on to promote discharging of the block (Patent Document 1).    Patent Document 1: Japanese Patent Application Publication No. 2009-278709